Abstract: In order to study the formation and propagation mechanism of stress cracks in brown rice under mechanical force action, the compressive mechanical properties of brown rice with white heart, white abdomen and non-chalky brown rice were measured by TMS-PRO texture analyzer respectively, and the brown rice were observed by section microscopy before and after the experiment treatment. The results showed that the compression force that non-chalky brown rice and abdominal brown rice could bear was greater than that of heart brown rice, but the compression force that non-chalky brown rice and abdominal brown rice could bear was not significantly different. Analysis of microscopic images showed that discontinuous microcracks already existed in the normally harvested brown rice grains. After being subjected to mechanical force, continuous microcracks formed in the brown rice grains and radiated to the epidermis at the center of endosperm.